No summation showing for the variable in the return statement

Hi ,I think it's better If you divide this into few parts

first calculated sum of balance for FL P1

SumBalance_Flp1 = 
CALCULATE(
    SUM(fy_prev[balance]),
    fy_prev[conditional_column] = "FL P1"
)

then sum of balance for ML P1

SumBalance_mlp1 = 
CALCULATE(
    SUM(fy_prev[balance]),
    fy_prev[conditional_column] = "ML P1"
)

and the value coming from s90 table

S90 value = 
CALCULATE(
    SUM('S90 (2)'[WRITTEN OFF BAL]),
    'S90 (2)'[DOM] = "MPA",
    'S90 (2)'[P_TYPE] = "JDS Loans P2"
)

and then next you can create the the measure you want 

Measure_6new = 
VAR S17 = 33726
VAR S16 = 4135
RETURN
    [SumBalance_mlp1] + [S90 value] + S17 + S16

Total Amount outstanding = 
VAR S17 = 33726
VAR S16 = 4135
RETURN
[S90 value] + [SumBalance_Flp1]+ S17 + S16